[R-pkg-devel] Depending on currently unreleased package

[William Brannon]

Thanks! That took care of it. I had been tripped up by how the R support in
travis-ci throws errors if suggested packages aren't available.

On May 6, 2017 4:18 PM, "Duncan Murdoch" <murdoch.duncan at gmail.com> wrote:

> On 06/05/2017 4:02 PM, William Brannon wrote:
>
>> Hi r-devel,
>>
>> I have a package called sqlscore (
>> https://cran.r-project.org/package=sqlscore) which depends on dplyr
>> functions for SQL generation. The new version of dplyr splits these
>> functions into a different package (dbplyr) and provides a recommended way
>> to wrap around access to the function in the appropriate package. So when
>> it's released in a few days, users with the new dplyr will see errors when
>> trying to use sqlscore. So far, so good, though - updating my R code as
>> such isn't hard.
>>
>> But dbplyr won't be released before the new  dplyr is, and I can't figure
>> out how to list it in Imports, Depends or even Suggests to release an
>> update ahead of the new dplyr release. Doing so causes ERRORs in R CMD
>> check about an unavailable dependency, and not doing so causes problems
>> with "::" references to a package not mentioned in DESCRIPTION.
>>
>> I'd rather not wait until dbplyr is released to submit a new package, for
>> obvious reasons. But releasing an update which depends on it before that
>> might also cause breakage.
>>
>> Any suggestions for the right upgrade path?
>>
>>
> You can list dbplyr in Suggests, and put in conditionals to test for it.
> If you don't want to wait for its release you'll need to have code that
> works without it as well, so something like this
>
> if (requireNamespace("dbplyr"))
>   foo <- dbplyr::foo
> else if (packageVersion("dplyr") < "x.y.z")
>   foo <- dplyr::foo
> else
>   stop("You need to install the dbplyr package, because dplyr::foo has
> moved there.")
>
> will allow you to use foo() anywhere (as long as its interface is the same
> in both packages, of course).
>
> Duncan Murdoch
>

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